Page 467 - Problem-Based Feline Medicine

22 – THE CAT WITH ABDOMINAL DISTENTION OR ABDOMINAL FLUID 459

Alternatively, severe inflammatory bowel disease Biopsy of gastrointestinal tract or other abdominal
may actually represent an indolent lymphoma. organ.
A progressive course of disease is more consistent ● In addition to making a diagnosis, the biopsy
with lymphoma while a waxing and waning course should be used to grade the lymphoma with respect
is more consistent with inflammatory bowel disease. to its aggressiveness. High-grade lymphomas are
● Alimentary lymphoma has historically been consid- poorly differentiated and may be further character-
ered to be primarily of B-cell origin. There is ized as immunoblastic or lymphoblastic. Low-
increasing evidence of T-cell alimentary lymphoma, grade lymphomas are well differentiated and may
especially with low-grade lymphomas. also be referred to as lymphocytic. Intermediate
forms also occur. The percentage of cell types
Solitary hepatic, splenic or renal lymphoma may also
varies between studies, but overall low-grade lym-
occur.
phomas are less common than intermediate and
Abdominal lymphoma may cause abdominal disten- high-grade lymphomas.
tion by hepatomegaly, splenomegaly, gastrointesti- ● Lymphocytic gastrointestinal lymphoma may have
nal thickening or dilation, or fluid. a tendency to be epitheliotropic (to involve the
● Abdominal lymphoma may cause ascites by portal mucosa) and to be of T-cell origin.
vein compression, lymphatic obstruction, septic
FeLV and FIV tests should be obtained.
peritonitis secondary to intestinal perforation and
spontaneous hemorrhage. Iron-deficiency anemia from chronic gastrointestinal
hemorrhage may occur with alimentary lymphoma.
Clinical signs Peritoneal fluid may be a transudate, modified tran-
sudate, septic exudate, chylous or hemorrhagic effu-
Multicentric nodal lymphoma:
sion, and may contain neoplastic cells.
● Variable lethargy, inappetence and weight loss.
Some cats have no systemic signs.
● Generalized moderate to marked painless periph- Differential diagnosis
eral lymphadenopathy.
Differential diagnoses for generalized lymphadeno-
● Variable hepatomegaly and icterus, splenomegaly,
pathy include atypical hyperplasia, hyperplasia in response
abdominal distention (uncommon).
to generalized skin diseases, immunologic disorders and
Alimentary lymphoma: systemic infections, widely metastatic neoplasia, and
● Anorexia, inappetence and weight loss. generalized bacterial or fungal lymphadenitis.
● Variable vomiting and diarrhea, but absence of
Differential diagnoses for lethargy, anorexia, weight
these signs does not rule out alimentary lymphoma.
loss, vomiting and diarrhea include inflammatory
● Variable intestinal mass or thickening, organomegaly,
bowel disease, other gastrointestinal neoplasia, pancre-
icterus and abdominal distention.
atitis, systemic mycoses and cholangiohepatitis. Other
● Peripheral lymphadenopathy is uncommon.
than inflammatory bowel disease, these disorders may
Other abdominal extra-nodal lymphoma: also cause lethargy, anorexia and weight loss without
● Signs of specific organ failure, e.g. icterus with vomiting and diarrhea.
hepatic lymphoma.
Differential diagnoses for marked splenomegaly
● Variable organomegaly and abdominal distention.
include mast cell tumor and other tumors.
Diagnosis
Treatment
Abdominal radiography or ultrasonography may
demonstrate an intestinal mass or intestinal thickening, Chemotherapy as described in Chapter 31 Aggressive
splenomegaly, hepatomegaly, lymphadenopathy or lymphomas should be treated aggressively and indolent
peritoneal fluid. lymphomas should be treated more conservatively.